Printing telegraph apparatus



B. F. MADSEN PRINTING EELBGRAPH APPARATUS June 2, 1942.

Filed April 20, 1958 4 Sheets-Sheet 1 lmnentor BERTHEL F. MADSEN GttomegJune 2, 1942. a. F. MADSEN PRINTING TELEGRAPH APPARATUS Filed April 20,

1938 4 Sheets-Sheet 3 FlG.8

Patented June 2, 1942 PRINTING TELEGRAPH APPARATUS Berthel F. Madsen,Chicago, 111., assignor to Teletype Corporation, Chicago, Ill., acorporation i 'of Delaware Application April 20, 1938, Serial No.203,021

12 Claims.

This invention relates to printing telegraph apparatus, and particularlyto printing telegraph apparatus in which the characters are printed inpage form from type elements carried upon the periphery of a rotatableand selectively arrestable type wheel.

An object of the invention resides in the provision in a printingtelegraph receiving unit embodying a selectively rotatable type wheelwhich is shiftable into and out of printing position to affordvisibility, of instrumentalities for controlling the shifting of thetype wheel and for arresting it at various elevational positionsrelative to the printing level.

Another object of the invention is to divide the performance of afunctional operation in a printingtelegraph receiving unit between twocam assemblies supported by asingle driving shaft but independentlydriven thereby in overlap relation. I

The invention features, in a printing telegraph receiving unit embodyinga type wheel having a plurality of rows of type elements about theperiphery thereof and supported by an oscillatable frame, a plurality ofstop elements for arresting the type wheel supporting frame in variouspositions alternatively under the control of the case shift functionmechanism of the receiving unit. The inventionalso features anarrangement for driving the operating cams of a printing telegraphreceiving unit in which there is a plurality of cam assemblies carriedby a driving shaft, one of the cam assemblies including cams forperforming certain operations, and in addition,

a cam for controlling a pawl and ratchet combination through whichrotation is imparted by the driving shaft to the other cam assembly.

In a copending application, Serial No. 77,796, filed May 4, 1936, byAlbert H. Reiber, there is disclosed a type wheel printer with referenceto which the present invention stands as an improvement. According tothe disclosure of that application, the type wheel is slidably supportedupon the type wheel shaft by a frame which may occupy either of twopositions and may be shifted from one to the other of the two positionsunder the control of the case shift mechanism for aligning either of tworows of type elements carried by the type wheel with the level at whichprinting is to be effected. When the type wheel has been shifted to agiven position by the shifting of the supporting frame, it remains inthat position until a case shift signal assigned to the shifting of thetype wheel to its other position has been received and renderedeffective.

According ot the present invention, the type wheel is movable axially ofthe type wheel shaft and is supported by a shiftable frame, the normalposition of the frame being such that the entire type wheel is heldbelow the level at which printing is to be effected so that a line whichis being printed, including the last character, shall be visible. Foreach cycle of operation of the receiving unit, the type wheel supportingframe is oscillated so as to bring the type wheel into printing positionbefore the printing operation occurs and to restore it to normalposition after the printing of a character has been accom plished. Inthe preferred embodiment of the invention, the type wheel supportingframe is moved by a cam to bring the type wheel into printing positionbefore the printing operation and is restored to normal position underthe control of a cam. The cam which elevates the type wheel to printingposition imparts suflicient motion to bring the type wheel above theuppermost of its printing positions. A plurality of stop elements areprovided, one for arresting the type wheel in each of the elevationalpositions from which it may be desired to effect printing. The severalstop elements are rendered effective alternatively by the shift andunshift function mechanism of the receiving unit, so that these .ill

function mechanisms, instead of shifting the type wheel to the desiredposition, as in the disclosure of the hereinbefore mentioned copendingapplication, merely operate to arrest the type wheel in the desiredposition. The type wheel elevating mechanism includes a yield, so thatthe type wheel may be arrested short of its uppermost position whilepermitting the elevating cam and part of the elevating mechanism tooperate as if imparting full movement to the type wheel.-

Several embodiments of mechanisms for arresting the movement of the typewheel under the control of the shift and unshift mechanism aredisclosed.

The disclosure of the .copending application reveals that the transferoperation, by which the code discs of a code disc selector are set inaccordance with a new signal combination and the type wheel is releasedfor rotation to a new position of arrestment corresponding to thetransferred signal, is performed by a cam included in a cam assemblywhichalso includes the cam for performing the printing operation. Theprinting operation is timed to precede the transfer, the reason for thisbeing that the interval of time which it is desirable to allot torotation of the type wheel to a new position of arrest- 'transferoccurs.Consequently, the print operation is timed to occur substantiallyimmediately after the beginning of the next cycle of operation of thecam assembly and the result is. as described 'in the copendingapplication, that the printer comes to rest with a signal combinationstored in the code disc selector mechanism which would not becleared outuntil the next cycle of operation of the .cam assembly. If the: signalcluding alternative embodiments of the shift and -unshift functionmechanism;

Fig.8 is a perspective view of an alternative arrangement of operatingcams wherein two operating assemblies are carried by a single drivingshaft and are independently driven therefrom, affording the possibilityof 'nearly a full cyclic interval of lag of one cam assembly behind theother cam assembly; 7

Fig. 9 is an elevational view partly in section of the apparatus shownin Fig. 8;

Fig. 10 is a plan view of the mechanism shown I in Figs. 8 and 9;

combination which is stored represents the last character of a message,it is necessary to introduce an idle operation of the printer in orderto print the character for the selection of which the type wheel hasbeen rotated in response to the.

signal combination stored in the code disc selector.

According to the'present invention, the cam which controls the printingoperation has been removed from the cam assembly which includes thetransfer cam and has, according to one embodiment, been'lncluded in aseparate cam assembly carried by a shaft separate from that whichsupports the transfer cam assembly, and according to another embodimenthas been included in a cam assembly which is carriedby Fig. 11 is anelevational view partly in section of an alternative arrangement ofoperating cam assemblies wherein two cam assemblies are carried bya'single driving shaft and are independently driven therefrom, thearrangement affording only a fractional cyclic lag of one cam assemblybehind the other cam assembly; and

Fig. 12 is a plan view of the apparatus shown the same shaft thatcarries the transfer cam assembly, but which is independently driven.The latter embodiment is disclosed in two variations, in one of whichthe operating cycle of the printing cam may occur almost entirely afterthe transfer cam assembly has reached its rest position, which is trueof the embodiment employing the two driving shafts, and in the other ofwhich the cycle of the printing dam may lag behind the transfer cambyonly a relatively small I fraction of a cyclic interval. v

Certain features of invention disclosed but not claimed herein are alsodisclosed and are claimed in copending applications, Serial No. 193,642,filed March 3, 1938, by Albert H. Reiber; Serial No. 208,761, filed May19, 1938, by Edward S.

' Larsen; Serial No. 204,038, filed April 25, 1938,

transmitting and receiving mechanism accordinvention.

Referring now to the drawings and particularly to Fig. 1, the referencenumerals l6 and I1 designate generally the typing unit and keyboardtransmitter unit, respectively, of a printing telegraphapparatusembodylng the present The keyboard transmitter unit I1 isgenerally similar to the transmitter disclosed in copending application'Serial No. 77,796, filed May 4, 1936, by Albert H. Reiber, and typingunit I6 embodies improvements on the typing unit disclosed in thecopending application.

The foundation of the keyboard transmitter unit is the base casting l8to the forward verticalwall of which is secured a slotted comb IS. Aplurality of key levers 2| are pivoted within the casting l8 for rockingmovement in a vertical plane, and these key levers protrude from theinterior of base l8 through a slot in comb l9.

The key levers2l are provided with keytops 22 and are arranged to impartcharacteristic settings to permutation code bars contained within baseI8 as fully disclosedin Patent No. 1,595,472 granted August. 10, 1926,to Howard L. Krum. To the code bars are articulated lock levers 23pivotally supported intermediate their ends and projecting above theupper surface of base casting l8 through apertures therein. The locklevers ing to the present invention, certain portions anism thereto;

Fig. 4 is a schematic elevational view showing an altemative'arrangementfor oscillating the type wheel and for printing; a

Fig. 5 is a schematic elevational view showin another alternativearrangement for oscillating the type wheel and for printing, andincluding an alternative embodiment of the shift and un- I shiftfunction mechanism;

Figs. 6 and 7 are schematic elevational view predicated upon thedisclosure of Fig. 5 and in- 23 are therefore subject to permutativesetting by the code bars under the control of key levers 2|.

The upwardly projecting portions of the lock levers 23 are disposedbetween brackets 24 and .26 secured to base I 8, and aligned; with eachof the lock levers 23 is a contact controlling lever 21, the levers 21being pivotally supported bya pivot rod (not shown extending betweenbrackets 24 and 26. A, transmitting contact spring 28 individual togeachof the levers 2'l'is mounted between insulating strips upon laterallyextending portions of brackets 24 and 26, as in-Q dicated at 29. Theupperend of each contact spring 28 engages a gooseneck portion of lever21 and the flexing of contact spring 28 into and, out of engagement witha shorter associated conthe reference numeral 3| rotatably support asigaaeaece m Li naltransmitting distributor shaft 33. Near one whichcorresponds to the interval in which the end shaft 32 has securedthereto a gear 33' to which rotation is continuously imparted by anothergear as will presently appear. Adjacent to gear 33, shaft 32 has securedthereto the driving element 34 of a jaw clutch. A driven clutch element36, slidable upon shaft 32, is keyed to a cam sleeve 31 and is urgedtoward clutch driving element 34 by a compression spring 38. A pivotedclutch throwout lever 39 normally holds driven clutch element 33 out ofengagement with driving element 34 against the force exerted bycompression spring 38. Clutch throwout lever 39 has an arm 4! whichterminates substantially in engagement with an abutment screw 42carried-by a clutch tripping bell crank 43. A depending arm 44 of bellcrank 43 has its outer end disposed in the path of a lug 46 carried by alink 4! which enters the keyboard base [8 and is there connected to auniversal bail (not shown). When link 41 is shifted forwardly of thekeyboard transmitter base by operation of the universal bail under thecontrol of one of the key levers 2|, it rocks bell crank 43 clockwisewhich, in turn, trips clutch throwout lever 39 and permits spring 38 toshift driven clutch element 36 into engagement with driving element 34.As link 41 is moved forward, it is cammed downwardly by cooperation of acam projection 48 with the head of a screw 49 carried by a forwardlyextending portion of bracket 25. The cumming of link 47 downwardlypermits the free end of arm 43 of bell crank 43 to escape from lug 46 sothat bell crank 43 may return immediately to its extremecounterclockwise position and permit clutch throwout lever 39 to returnimmediately into position for arresting the clutch comprising elements34 and 36 at the conclusion of one revolution thereof, even though a keylever should be held depressed and link 41 retained in its forwardposition for a prolonged interval of time. Thus the operation of camsleeve 37 by the jaw clutch is confined to a singe revolution inresponse to each operation of a key lever. A tension spring i maintainsengagement between cam projection 48 of link 41 and the head of screw49.

The cam sleeve 31 carries a lock bail operating cam 52 and a pluralityof impulse timing cams 53. Cam 52 controls the operation of a lock bail54 pivotally supported by brackets 24 and 26, lowering the bail intoblocking relation to the lock levers 23 as the cam sleeve 3! begins torotate, and lifting it at the end of a cycle. The

function of thelock bail 54 is to prevent the shifting of lock levers 23during a cycle of rotation of the impulse timing cams 53 and thusprevent mutilation of a signal combination established by the depressionof a key lever 2|. Each of the cams 53 is aligned with one of thetransmitting contact control levers 21 and is engaged by a portion ofthe aligned lever. Each of the cams 53 has a notch 56 in the peripherythereof which, when presented to the associated transmitting contactcontrol lever 21, releases that lever for rocking movement incounterclockwise direction, and the lever 21 rocks unless restrained byits associated lock lever 23. The recesses 56 in the several cams 53 arearranged spirally about the cam assembly so that the levers 21 arereleased for rocking movement successively. When a lever 21 is permittedto rock counterclockwise by its cam 33, its contact spring 21 flexesinto engagement with the associated short contact spring and a currentimpulse is impressed upon the telegraph line, the duration of lever 21remains in its counterclockwise position. The cams 53 thus distribute tothe telegraph line the signal impulses corresponding to a characterrepresented by a key lever depressed. One of the contact controllinglevers-21 has no lock lever associated with it and operates invariablyonce in each cycle of operation of the transmitting cam for impressingon the line the stop impulse.

The principal foundation element of the typing or receiving unit is acasting which mounts on the keyboard base l8 and has a portion 6|located centrally of the base [8 and a portion 62 extending transverselyof the base l8 in proximity to the rear edge thereof. Thumb screws areem ployed for securing the casting comprising portions GI and 62 to thebase I8, one of those screws being indicated at-63. A secondary casting64 extends transversely of the keyboard base l8 and is secured toportion 62 of the primary casting by any desired means, such as screws.The primary casting supports all of the power driven shafts, theoperating cam assemblies, the selector mechanism, the. printingmechanism, and the ribbon feed mechanism. The secondary casting 64supports the platen carriage and associated mechanism, the signal bells,and a set of levers by which various functions are performed.

The primary selector mechanism which integrates the signal combinationsgenerated in the keyboard transmitter mechanism, hereinbefore described,or in a remote transmitter, is indicated generally by the referencenumeral 66 and is generally similar to the primary selector mechanismdisclosed in the hereinbefore identified copending application of AlbertH. Reiber, Serial No. 77,796. The principal elements of the selectormechanism 66 are a selector cam assembly 61, a selector magnet 63, and asword and T-lever assembly 69, the last mentioned assembly as well asthe selector magnet being supported by a mounting plate H carried by theforwardly extending portion 6| of the primary casting. The selector camassembly 61 is carried by the upper end of a vertically positioned shaftwhich is rotatably supported in bearing blocks 12 and 13. The selectorcam assembly 61 has flanges 14 secured thereto at opposite ends, and inspaced relation to each flange 14 is a flange 16 secured to the shaftwhich supports the cam assembly 61. A friction disc H occupies the spacebetween each of the flanges l4 and the adjacent flange l6. Considerablefriction is generated between the discs 11 and those positioned oneither side of them so that selector cam assembly 6'! will rotate withits supporting shaft except when restrained under the control ofselector magnet 58, as is well known in this type of single magnetselector mechanism.

Just above the point at which it enters lower bearing block 72, theshaft has secured thereto a gear 18. An electric motor (not shown)drives a pinion which meshes with gear 18 so that the shaft to which thegear 78 is secured is continuously rotated. It may be added at thispoint that a gear 19 carried by a stub shaft meshes with gear 18 andthat a spiral gear 8| also secured to the stub shaft meshes with gear 33carried by the transmitter shaft 32. Thus rotation is imparted to thetransmitting distributor shaft 32 from the motor pinion through gears18, 19, 8|,and 33.

The sword and T-lever mechanism 69 is actuated under the joint controlof selector cam code discs of a code disc selector mechanism indicatedgenerally by the reference numeral 84.

The code disc selector mechanism 84 has a circular arrangement ofvertically positioned stop pins 88 which project through slots in thetopmost plate of the mechanism. Stop pins 88 are biased inwardlyradially of the code disc selector mechanism and near their upper endsthey rest against-the edges of shiftable notched code discs as is fullydisclosed in the copending application of Albert H. Reiber, Serial No.77,796. The

notching of the code discs is such that forany permutative setting ofthe discs under the control of T-levers 82 one only of the stop pins 88finds presented to it an alignment of notches, whereupon the pintherefore enters the alignment of notches under the influence of itsbiasing spring, its upper and moving inwardly. A type wheel stop arm 81clamped to type wheel shaft 88 is of such length that in revolving, itjust clears those of the stop pins 88 which are held in their outermostpositions by the code discs, but finds blocking its path any pin 88which has entered an alignment of notches in the periphery of the codediscs. The type wheel shaft 88 extends downwardly through the code discselector mechanism 84 coaxially thereof and receives a continuous torquefrom the driving motor through any convenient means, such as a gearcarried by the shaft 88 and connected thereto by friction discs, thegear being continuously position in which stop arm 81 encounters a'stoppin 88.

The setting of the T-levers 82 according to the operation of the swordlever mechanism 88 is controlled by a transfer bail 8| which is camoperated as will presently appear. Transfer bail 8| is pivotallysupported by an upper mounting screw 82 and by a lower mounting screwwhich does not appear in Fig. 1. Transfer [bail 8| is biased incounterclockwise direction by tension spring 83 and has oppositelyextending arms 84 and 88, the former of which is only partiallyindicated in Fig. 1 but which supports transfer springs. as is clearlyindicated in the copending application Serial No. 77,796, and the latterof which carries a locking blade 81 that cooperates with extensions 88to T-levers 82. Looking blade 81 ordinarily blocks the extensions 88 ofT-levers 82 whether they be presented in extreme clockwise orcounterclockwise position. The rocking of transfer bail 8| in clockwisedirection to effect the resetting of T-levers 82 is accompanied bywithdrawal of locking blade 81 out of the path of movement of T-leverextensions 88. When the transfer has been completed, transfer bail 8|returns to its extreme counterclockwise position and locking blade 91 isrestored to locking position with respect to extensions 88.

The front portion 8| of the primary foundation casting for the typingunit has secured therebrackets IN and I82.

cation Serial No. 165,437, filed September 24;"

1937, by B, F. Madsen, having in its periphery a groove designated I08in the present application, which receives the portion III of the clutchthrowout lever H2. The portion III of the clutch throwout lever II2confines driven clutch element I88 to substantially complete engagementwith driving element I81 during a cycle of operation following thetripping of the clutch, and prevents acceleration of the driven elementof the clutch from the speed imparted to it by the driving element I81,should any torque generated by negative load resulting from theinteraction of a cam follower and its cam be applied to the drivenclutch element I88. Driven clutch element I88 is slidably splined orkeyed to a cam assembly sleeve 8 and is urged into engagement withdriving element I81 by compression spring II4.

Clutch throwout lever I I2 is carried by the lower end of a pivoted bailII8, the upper pivot of which is designated II1. At its upper end, bailH8 is provided with an arm II5, the free end of which is disposed in thepath of the lowermost cam projection I28 of selector cam assembly 81.Bail H8 is biased in counterclockwise direction by tension spring I2 I.When cam projection I28 on selector cam assembly 81- encounters arm "8of bail II8, the ball is rocked in clockwise direction, thus withdrawingclutch throw-out lever I I2 from restraining engagement with the drivenclutch element |88-of the clutch on the front shaft. and permittingdriven element. I88 to move into engagement with driving element I81whereby rotation is imparted to cam sleeve II3.

Cam sleeve I I3 supports three cams designated II8, II8, and I25. Cam 8is engaged by a follower roll I22 carried by an .arm I23 secured totransfer bail 8|. The direction'of rotation of cam sleeve 3 iscounterclockwise and cam II8, in being rotated, imparts clockwiserotation to arm I23 and therefore to transfer bail 8|. Transfer bail 8|,as previously set forth, efiects the permutational rearrangement ofT-levers 82 and therefore the notched code discs in the code discselector mechanism 84 in accordance with a signal combination which hasbeen integrated in the sword lever mechanism 88.

As previously set forth, there is a shaft rotatably supported invertical position by bearing blocks 12 and 13 to which the gear '18 issecured.

Below bearing block 13 the shaft has secured. thereto the drivingelement I24 of a positive drive clutch, the driven element of which isdesignated I28. Driven element I28 is slidably splined or keyed to amain cam assembly I38 unit and terminates in the path of the apex of camH8 carried by cam sleeve H3 on the frontshaft. As indicated in Fig. 1,in which the clutch mechanism on the shaft and on the main cam drivingshaft are shown in their rest positions, the rest position of the apexof cant I I6 is a small angular distance in counterclockwise directionfrom the end of arm I28 which effects the tripping of the main camclutch comprising elements I24 and I29. Since, as previously stated, camcylinder H3 rotates in counterclockwise direction, it will be apparentthat cam II8 operates upon arm I28 to effect the tripp ofdriven clutchelement I29 just before cam H8 reaches the end of a cycle of operation.

The bracket IIII which rotatably'supports the upper end of shaft I83pivotally supports a ball I3I, the pivot being designated I32. The bailI3I supports a cam follower arm which'has been omitted from the showingof Fig. 1 for the reason that it would conceal-substantial portions ofthe main cam assembly I30 carried by the rotatable shaft which issupported in bearing blocks 12 and 13. The cam follower arm carries atits free end a follower roll which engages cam I25 at a point betweencam assemblies H3 and I24. The contour of cam I25 comprises a smoothgradual rise and a sharp drop-off, the drop-off being indicated by areference numeral I33. As cam I25 rotates counterclockwise, it shiftsits follower roll away from the axis of shaft I63 and thus imparts acounterclockwise rotation to bail I3I. In the rest position of cam I25,the drop-off I33 is a small angular distance beyond the point ofengagement of the cam follower roll with cam I25. The'tendency of thecam I25 therefore is to permit bail I3I to return sharply to its extremeclockwise position just before cam I25 reaches its rest position.However, as will presently appear, a cam included in the pain assemblyI36 assumes control of bail I3I just before the sharp drop-off I33 incam I25 is presented to its follower, and the cam in cam assembly I30holds bail I3I in extreme counterclockwise position for a predeterminedinterval and thereafter controls the restoration of bail I3I to itsextreme clockwise position.

Bail I3I has integraltherewith an arm I34 which extends toward the rearof the typing unit and terminates in a spring hanger hook I36. HookI36-supports one end of a tension spring I31, the opposite end of whichis connected to an arm I38 of a type wheel supporting frame I39.

Frame I39 is provided with a vertically disposed slot I'4l, throughwhich extends a stud I42 supported by a portion of the frame of thetyping unit. At the top, frame I39 has a horizontally extending portion.I43 through which type wheel shaft 88 passes and in which is rotatablyheld the hub of a type wheel I44. Vertically disposed 60 guide pins I46,only one of which appears in Fig. 1, are supported by a stationarybracket I41 at the top of the typing unit and pass through apertures inthe horizontal portion I43 of type wheel supporting frame I39. The pinsI46 and the cooperating elements comprising slot HI and stud I42 permitoscillatory movement of frame I39 vertically, and guide the frame inthat movement. Frame I39 is provided with an abutment screw I48 againstwhich arm I34 of bail I3I rests when the bail I3I is in extremeclockwise position and frame I39 is in the lowermost position. When bailI3I is rocked in counterclockwise direction by cam I25, bail arm I34tends to move out of engagement with abutment screw I48 and spring I31tends to be distended. Spring I31, in turn, lifts frame I39 and thustype wheel I44, the normal position of which is below the print- 5 ingline, is elevated so' as to bring character elements carried upon theperiphery'of the type wheel into position to effect printing in lineupon a page carried in engagement with cylindrical platen I49. When bailI3I is restored to its ex treme clockwise position, arm I34 engagesabutmerit screw I48 and restores frame I39 to its lowermost positionwhich, in turn, restores type wheel I44 to its lowermost'position,whereby each character becomes visible immediately after bel5 ingprinted.

As previously set forth, main cam sleeve I38 is set in operation by thetripping of clutch throwout lever I21 by cam II8 included in front camassembly 3 just beforecam H8 reaches its rest position. The uppermost ofthe cams carried by cam assembly I36, designated I5I, is engaged on the'periphery thereof by a follower roll I52 carried at the end of a leverI53 which is pivoted at I54. Lever I53 has integral therewith an arm I56which is provided near its outer end with a plurality of springconnection apertures I51. Any one of the apertures I51 is adapted toreceive one end of a tension spring I58, the other end of which issupported by a spring post I59. Spring I58 biases lever I53 incounterclockwise direction, thus urging cam follower roll I52 intoengagement with the periphcry of cam I5I. The several spring mountingapertures I51 in arm I56 of lever I53 are at different distances fromspring post I59 so that the H tension exerted by spring I58 andtherefore the torque applied to lever I 53 may be varied.

A print hammer operating bail I6I is pivotally supported by pivot I54and coaxially mounted 4" pivot I62. At its lower end, bail I6I isprovided with an arm I63 which supports adjustable abutment screw I64and also one end of a tension spring I66. The inner end of abutmentscrew I64 engages an arm I61 of lever I53 and the rearmost end oftension spring I66 is also connected to arm I61 oflever I53. With thisarrangement, bail I6I tends to occupy extreme clockwise position withrespect to lever I53, the extremity of the position being determined byabutment screw Print hammer operating bail I6I has integral I therewithat its upper end a lever arm I68. At its free end, lever arm I68 isloosely articulated to a print hammer I69. Print hammer I69 extendsbetween ribbon spools I'II, rotatably mounted upon a ribbon feedmechanism supporting plate I12. Print hammer I69 is provided with upperand lower arms I13 and I14, respectively,

which are disposed in the same verticalplane. Lowerarm I14 enters a slotin a bracket I16, carried by ribbon feed mechanism foundation plate I12,and by means of slotted bracket I16, print hammer I69 is held in avertical plane and is guided in reciprocatory motion imparted by 65 armI68 of bail I6I. The upper arm I13 of print hammer I69 is longer thanthe lower arm I14 andextends across the periphery of type wheel I44 andacross the upperend of type wheel shaft 38. At its free end, arm I13 isprovided with a 70 depending portion I11 which, in turn, is providedwithan arm I18, the location ofwhich is in alignment with the foremostportion of platen I49, which portion is at the level where printingoccurs, Print hammer I69 is provided in its lower edge with a shallowrecess I16, the base of which rests upon and slides upon a retainer barI15 secured to ribbon mechanism base plate I12. The motion of printhammer I69 to effect printing is limited by engagement of oneend ofrecess I10 with bar I16, and the restorational motion may, if desired,be limited by engagement of the other end of recess I10 with bar I15.

The print hammer I69 may be lifted out of its position above the typewheel I44 to permit ad- Justing or changing the type wheel, by springingthe free end of print bail arm upwardly until the rearmost end of recessI10 clears bar I15, whereupon arm I14 of the print hammer may be drawnclear of slotted bracket I16, and the print hammer may be rotatedupwardly in a vertical plane about its pivot of articulation with ballarm I68.

Typewheel I44 may be generally similar to the type wheel disclosed inthe hereinbefore identifled application of Albert H. Reiber, Serial No.77,796, and also in application Serial No. 77,794, filed May 4,-1936, byHoward L. Krum et a1. As shown in those copending applications and asclearly indicated in Fig. 1 of the present application, type wheel I44is provided with a plurality of radially disposed type pallets I19 whichare reciprocably mounted in radial slots in type wheel I44, and areprovided at their outer ends with type elements I 6|. There may be twosuperposed rows of type pallets I19, and by means of the lifting of typewheel supporting frame I39 by lever I34, either of the rows of typepallets may be brought into alignment with rearwardly presented portionI18 of print hammer I69. For .any angular position of arrestment of typewheel I44 by the cooperation of type wheel stop arm 61 with a selectedstop pin 86, two of the type pallets I19 will be directed toward platenI49 in the same vertical plane as print hammer I69. According to thedistance that type wheel I44 has been lifted by lever arm I34, thedistance bein controllable, as will appear later, one or the other ofthe type pallets I19 will be disposed directly in the path of portionI18 of print hammer I69.

Cam I5I, in its normal or rest position, holds print bail operatinglever I53 in extreme clockwise position in opposition to the tension ofspring I58. Spring I66 holds print hammer-bail I6I in extreme clockwiseposition with its abutment screw I64 in engagement with an arm I61 ofprint bail operating lever I53. Thus, print hammer I69 is held inretracted position. At a predetermined time in the operation of cam I5I,a sharp drop-off is presented to follower roll I52 of print bailoperating lever I53. When the dropoff is encountered, lever I53 isrocked sharply in counterclockwise direction by spring I58. .Lever.I53'imparts counterclockwise movement to bail I6I through abutmentscrew I64. distance through which lever I53 rocks, as cam The angularfollower I52 descends to the lowest or innermost point on the peripheryof cam I5I, is just short of suflicient to drive print hammer I69positively against the. type pallet I19 aligned therewith. However, theinertia of bail'I6I and print hammer I 69 causes spring I66 to yield andabutment screw I64 to move out of engagement with arm I61. Thus printhammer I69 overtravels or moves a greaterdistance than it would ifposipended, spring I66 withdraws print hammer III in the direction ofits retracted position until abutment screw I64 returns into engagementwith arm I61 oflever I63. The remainder of the movement of print hammerI69 to its rest I44 to effect printing. During the period of overtraveland restoration, the free end of arm I13 'of print hammer I68 ispresented between the type pallets adjacent to that which is beingoperated, so that the type wheel I44 could not be rotated, even ifpermitted to do so by arm 81, due to the fact that interference betweenarm I13 of print hammer I66 and adjacent unoperated type pallets wouldoccur. Spring I66 withdraws print hammer I69 from a position ofinterference with unoperated type pallets much more rapidly than itcould be withdrawn if positively connected to print hammer bailoperating lever I53. Thus, with the arrangement hereinbefore described,the print hammer I69 is projected and retracted in the shortest possibleinterval of time so that more time may be allowed for the rotation oftype wheel I 44 to the position corresponding to the next selection.

In a preceding paragraph, the lifting of the type wheel to bring eitherof its two rows of type pallets into printing position was described.The lifting is accomplished by the counterclockwise rocking of bail I3Iwhich has an arm I34 interconnected with the type wheel supporting frameI39 by spring I31. It was stated that the lifting of the type wheelsupporting frame I39 is effected by a cam I25 on the'front shaft. Itwasalso stated that the lowering of type wheel supporting frame I39 iscontrolled by a cam included in the cam assembly I30 on the main shaft.This cam is indicated by the reference numeral I86, and is of theinternal species having its cam surface on the inside of a dependingperipheral flange. The internal cam surface is engaged by a followerroller carried at the free end of an arm I61, secured to type wheellifting bail I3I. Spring, I31 biases bail I3I in clockwise direction aspreviously set forth and, in so doing, urges the follower roller carried by arm I81 to seek engagement with the internal cam surface of camI86. Cam I86 does not have a restricting channel, so that the followercarried by arm I81 is free to be moved away from engagement with theinterior of the depending flange of cam I86 when bail I3I is rocked incounterclockwise direction by cam I25. During the initial stages of thelifting. of frame I39 by cam I25, cam I86 may be stationary.

About the time that cam I25 has rocked bail I3I to its extremecounterclockwise position, and before the drop-off of the camispresented to its follower roller, the innermost portion of the camsurface of cam I86 is presented in en-..

gagement with the follower roller carried by cam follower arm I 81.During the engagement of the follower roller carried by arm I81 withwhatever dwell there may be at the innermost portion of the internal camsurface of cam I66, bail I3I will be held inextreme counterclockwiseposition and lever'arm I34 will be held in a corresponding position. Ascam I86 continues to rotate and the receding cam surface is presented toits follower (the recession being ratrolled, is moved out of engagementwith its cam surface, and that when the frame I39 is being held inelevated position, and is being lowered, the cam follower by which itselevation was accomplished will be held out of engagement with theelevating ham.

Of the principal mechanisms of the typing unit Hi, there remains forconsideration only the function mechanism. This mechanism is, ingeneral, similar in construction and operation to the function mechanismdisclosed in the copending application of Albert H. Reiber, Serial No.71,796. The function mechanism may be understood to include thosemechanisms by which such operations as shift, unshift, carriage return,line feed, signal bell operation, and transmitter disablement areselected and accomplished. Those functions which are materiallydifferent from the corresponding functions, as disclosed in thecopending application of Albert H. Reiber, Serial No. 17,796, and whichwill be lection, is manifested by rotation of one or more of thefunction bars I93 through a small angular distance in clockwisedirection. Such rotational movement brings the conditioned function baroutof alignment with the unselected function bars and into position toinitiate or perform its assigned function. Immediately after theconditioning of one of the functionbars I93, cam 202 described indetail, are shift and unshift, by

means of which selection of characters in the letters or figures bank oftype pallets is accomplished.

The selection of a function is accomplished by means of a testingmechanism which is cam controlled. Since the testing operation can beconveniently performed by a groove or channel cam, a channel I9I isprovided in the upper surface of print bail operating cam I5I. A camfollower, which could not be shown in Fig. 1, is fitted into the grooveor channel I9I in cam I5I, and the follower arm is part of a bail I92which is operated to test for the selection of functions, and tocondition in accordance with the selection one or more of a plurality offunction bars, indicated generally by the reference numeral I93; Themanner in which the presence of a function is tested and in which thefunction bars I93 are conditioned is fully disclosed in the copendingapplication of Albert H. Reiber, Serial No. 77,796. I

The function bars I93 are pivotally mounted upon rod I94. Rod I94 issupported between spaced arms I96 and I91, which comprise a functionbail pivoted upon pivot rod I98. The lower arm-I91 of the function bailhas integral therewith an arm I99 at the free'end of which is supporteda cam follower roller 20I. A function cam 202, carried by the main camsleeve I30, has its periphery engaged by roller MI, and when cam 202occupies rest position, arm I99 and the function bail comprising armsI96 and I91 are disposed in extreme clockwise position.

At their free ends, the arms I99 and I91 support a spring post 203 towhich is hooked one end of each of a plurality of tension springs 204.Each of the springs 204 has its other end connected to one of thefunction bars I93. Thus, the function bars I93 are biased incounterclockwise direction, and movement of any of them in clockwisedirection is opposed by its particular tension spring 204.

The conditioning of function bars I93, under the control of bail I92 inresponse to a function serocks its follower arm 20I and the functionbail comprising arms I99 and I91 in counterclockwise direction. Sincethe function bars I93 are pivotally mounted upon rod I94, carried bybail arms I96 and I91, they are moved endwise'toward the rear of theprinter as cam follower roller 20I is moved to'its outermost positionwith respect to cam 202. Those of the function bars I93 which have notbeen conditioned by being rocked in clockwise direction are reciprocatedidly while one conditioned function bar I93 initiates or performs theassigned function as a result of the reciprocatory movement. The rodI94, carried by function bail arms I96 and I91, also is pivotallyengaged by a spacing pawl 206 which is reciprocated to effect spacing ofthe platen carriage as the function bars I93 are reciprocated rearwardlyof the printer. The spacing operation and the performance of the severalfunctions excepting shift and unshift are sufficiently similar to thosedisclosed in the copending application Serial No. 77,196, that it isconsidered unnecessary to describe them in detail here. However, theshift and unshift functions will now be described.

The hereinbefore identified stud I42, which guides the type wheelsupporting frame I39 in its upward and downward movements, extendsthrough a horizontally extending slot in a slide member201. The slidemember 201 is also provided with an open ended slot 208 through whichextends a screw 209, carried by the frame of the typing unit. The studI42 and screw 209support the slide member 201 and guide it throughout alimited sliding movement forwardly and rearwardly of the typing unit.

The slide member 201 has integral therewith a vertically extending arm2I I. The arm 2 is provided near its upper end with a step out aperture2 I 2. By virtue of the step cutting, two abutments or stop surfaces areprovided, the lower of which is indicated by the reference numeral 2I3,and the upper of which is designated 2| 4 and is the upper end of theaperture 2I2. The type wheel supporting and lifting frame I39 hasadjustably secured thereto a bracket 2I6, which has an arm 2I1,extending into the aperture 2I2 of the slide member 201. When the typewheel lifting frame I30 is lifted by bail arm I 34, operating throughspring I31, arm 2" of bracket 2l6 may encounter either of the stop,surfaces 2I3 or 2I4, depending upon whether the slide member 201 ispresented in its rearmost or foremost position, and thereby the typewheel lifting frame I39 will be arrested in either of two positions ofelevation while bail arm I34 continues to be rocked to its extremecounterclockwise position. When the type wheel lifting frame I39 isarrested by the lower stop surface 2| 3 'of slide member 201 the upperrow of type pellets carried by type wheel I44 is presented in alignmentwith the op- .erating extension I18 of print hammer I 09, and

I63, and with the character'impression level of the platen I29.

The movement of slide member 201 from one to the other of its twopositions is accomplished by two levers pivoted upon stud I42, one ofthe levers being pivotally supported between slide first and second ofthe function bars I93, counting from the top, each have extendinglaterally therefrom a lug, one of which appears in Fig. 1 and isindicated by the reference numeral 222. The depending finger 22I, oflever 2I9, occupies a position directly in the path of lug 222 when thefunction bar which carries lug 222 has been conditioned for functionperformance by being rocked in clockwise direction preparatory to beingmoved endwise by cam 202, operating through arm I and hail arms I96 andI91. When lever 2I9 is in its extreme counterclockwise position, whichis the condition when slide member 201 occupies the rearmost of itspossible positions, finger MI is disposed substantially at the limit ofmovement of lug 222 so that it will not be affected if the function barby which lug 222 is carried is conditioned and reciprocated.

When, however, the slide member 201 occupies the foremost position,lever 2 I9 willbe presented in extreme clockwise position and itsdepending finger 22I will be positioned to be engaged by lug 222, earlyin the cycle of movement of that lug rearwardly of the typing unit.Under these conditions, counterclockwise movement of lever 2I8 by lug222, as it moves rearwardly of the typing unit, will result in rearwardmovement of slide member 201 which is articulated to lever 218 by screw2 I 9, whereby slide member 201 will be shifted to its rearmost positionwith stop surface 2I3 in the path of arm 2 I 1 carried by type wheellifting frame I39. It will be understood that the timing of theapparatus. is such that type wheel supporting frame I39 is held loweredby bail arm I34 when slide member 201 is shifted so that there shall beno interference between arm 2" and the step-cut portion of aperture 2I2during the movement of slide member 201.

The restoration of the slide member 201 to its forward position isaccomplished by the lever which corresponds to lever 2 I8 and which ispivoted between slide member 201 and the frame member which supportsstud I42 so that it does not appear inFig. 1. A screw 223 establishes a.pivot connection between this lever and the slide member 201. Thispivotal interconnection is above stud I42 so that when the lever isrocked in counterclockwise direction, the slide member 201 will be movedforwardly of the typing unit to its foremost position. The lower end ofthe lever'which is pivoted to slide member 201 at 223 may be similar tothe lower end of -lever 21I8 so that when it is in extreme clockwiseposition, it will be disposed in the path of the laterally ex tendingprojection of that one of the function bars I93, -the.function of whichis to shift the slide member 201 to its foremost position to permit thetype wheel lifting frame I39 and the type wheel I44 to be lifted totheir uppermost position whereby printing may be effected from the lowerrow of type pallets.

It will be apparent from the foregoing description of the levers which,control the shifting of slide member 201 that both of these leversefl'ect control by being rocked in counterclockwise direction, one beingoperative to shift the slide member 201 rearwardly and the other beingoperative to shift it forwardly. It will also be apparent that as eitheris rocked in counterclockwise direction by its assigned function barI93, the motion which it imparts to the slide member 201 will cause theother lever to be rocked in clockwise direction so that they will bepresented alternately in position to be operated by their respectivefunction bars.

In addition to operating the function levers I93 and the spacing pawl206, the function bail also operates a ribbon feed lever 229. This leveris pivoted upon a stud 221 fixed to a stationary portion of the typingunit and its lower end engages the arms I96 and I91 of the functionbail. At its upper end, lever 226 is articulated to a link 228 which hasa slot in which is disposed one endof a ribbon feed lever 229. Theribbon feed mechanism which is operated by lever 229 may besubstantially identical with that disclosed in the copending applicationof Albert H. Reiber, Serial No. 77,796. The ribbon feed mechanismsupporting plate I12 supports pairs ofvertically disposed pins 23I whichserve as guides for the inked ribbon 232, and there is also asemicircular ribbon guide which is supported by the type wheel liftingframe I39 in spaced relation to the type wheel I44 between the typewheel and the platen I49. Thus, the ribbon guide 233 is lifted each timethe type wheel I44 is lifted, and a portion of the ribbon 232 is alwayspositioned between the type wheel I44 and the platen I49 so that inkedtype impressions may be produced upon a page carried by platen I49.

The platen I49 is rotatably supported by the opposed ends of a carriage236. The carriage is supported for movement transversely of the typingunit by rails, one of which is indicated as 231, secured to the rearcasting member 64. The casting 64 also supports near the top thereof abracket 238 which has a threaded aperture in coaxial relation to theplaten I49. A bushing 239 'threadedly engages the aperture in bracket238 and rotatably supports a square rod 24I which enters platen I49through one of the hubs therein and passes through a square portion of atube which extends from endto end of the platen I49. The square shaft 2is of sufficient length that it may extend into or through the squareportion of the tube on the interior of platen I49 in any position whichcarriage 236 may occupy in its travel back and forth upon its supportingrails. Square shaft 24I has secured thereto a crank 242 which may berotated manually to impart rotation to square shaft-24! and, through itscooperation with the square portion of the tube into which which itextends, rotation may be imparted to platen I49.

Carriage 236 also supports a paper guiding plate or basket 243 which isdisposed below the platen for guiding-a page in the printing positionand which, in turn, supports pressure rolls 244 and indicates a minalblock 25I has terminals 252 individually engaged by slip connectiontongues 253 carried by a slip connection block 25.4. ,Slip connectionblock 254 is secured to the rear portion 52 of the primary typing unitcasting belowthe secondary or carriage supporting casting. The contacts252 and tongues 253 may form electrical connections between theelectromagnet 60 carried by the typing unit and the transmitting contactsprings 21 carried by the keyboard base and between the selector magnetand external circuit. 7

Thus, the secondary casting and all of the ele ments which it supportsmay be removed from the typing unit without disturbing the electricalconnection between the selector magnet 60 and the transmitting contactsand between the external circuit and both the selector magnet and thecontacts. Also the entire typing unit may be removed from the keyboardbase by removal of the thumb screws 63 whereby the slip connectiontongues 253 will be removed from engagement with contacts 252 withoutdisturbing the electrical connections between the transmitting contactsand external circuit.

The general operation of the typing or receiving unit hereinbeforedescribed is as follows: Permutation code signals impressed upon atelegraph line to which the receiving unit is connected enter thereceiving unit at terminals 252 and slip conenction 253 and areimpressed upon the selector magnet 68. Gear I8 and the shaft which itdrives, being in operation, selector assembly 61 which is frictiondriven is released for a cycle of operation by the start impulse of asignal combination in accordance with the well-known practice employedin the operation of single magnet selector mechanisms controlled bystart-stop signals. As the selector cam assembly 61 rotates, the swordlevers contained in the sword lever mechanism 69 are set incharacteristic positions according to the signal combination received.Just before the selector cam assembly 61 completes a cycle of rotation,its I restraining engagement with driven clutch element I08, carried bythe front shaft, whereupon the driven element I08 is shifted intoengagement with driving element I01, and cam sleeve I I3 is set inoperation'for a cycle comprising one revolution.

The first operation performed after cam sleeve I I3 is set in operationis the clockwise rocking of transfer .bail 9|, by transfer cam IIS,operating through cam follower roller I22 and follower arm I23. Transferbail 9I operates to set the code discs contained in the code discselector mechanism 34 in correspondence with the setting of the swordlevers. The shifting of the code discs to accomplish the selection of anew stop pin 06 is accompanied by the camming of the previously selectedstop pin into unselected position whereby the restraint upon type wheelstop arm 31 is removed and shaft 00 and type wheel I44 rotate to seek anew stop position. At this time, the type wheel I44 is held in itslowermost position by the type As soon as the transfer has beenaccomplished,

.the selector cam barrel 61 may be released for rotationtbreffect thesetting of the sword 1eve rs according to a new signal combination. Thetiming of the operation of selector cam assembly 61 and of cam sleeveII3 carriedby front shaft I03 is such, with respect to the speed ofoperation of transmitting apparatus; in response to which this receivingmechanism is intended to operate, that the transfer has been effectedbefore the selector. cam barrel isreleased by the start impulse of thenext signal combination.

A predetermined interval after .the transfer operation has beenperformed, cam I25 begins to rock type wheel lifting bail I3I incounterclockwise direction and the type wheel I44 is elevated intoprinting position. The position in which the type wheel will be arrestedwill be determined by the position occupied by slide member 201. BailI3I will, however, be rocked to extreme clockwise position'regardless ofthe position in which type wheel I44 is arrested, spring I31 yielding topermit the motion of bail I3I to be completed.

A short angular distance before cam I25 has rocked bail I3I to extremecounterclockwise position, cam IIB, carried by cam sleeve II3, engagesclutch throwout lever I28 of the clutch which comprises driving elementI24 and driven element I 20 on the main shaft or inner cam shaft,whereby the main assembly I30 is set in 'opera tion; By the time cam I25has rocked type wheel lifting bail I3I to extreme counterclockwiseposition, internal cam I06, included in the main cam assembly I30, hasassumed control of its follower arm I81, which is carried by bail I3I,so that type wheel lifting bail I3 I is held in extremecounte'rclockwise position after cam I25 has come to rest and hasrelinquished control Over bail I'3I.

The front shaft may be rotated at the same speed as the main shaft sothat in the reception of signals continuously transmitted, the camsleeve I I3, carried by the front shaft I03, will have a rest periodbetween cycles of operation equal to the rest period of selector camassembly 61 between successive code combinations. Cam sleeve II3 may,therefore, begin its next cycle of rotation before the cam assembly I30,carried by the main or inner shaft, has completed much of its cycle ofoperation. While cam I06 is holding type wheel I44 elevated, and beforecam sleeve 3 can have rotated sufiiciently far in the next cycle tooperate the transfer bail, the print cam I5I brings its sharp drop offinto alignment with roller I 52, carried .by the print bail operatinglever I53, whereupon spring I 58 rotates lever I 53 sharply incounterclockwise direction and this movement is imparted to print bailI6I, which drives print hammer I09 into engagement v with the selectedtype-pallet and whichever-r travels .sufliciently to produce an impactbetween/ function that may have been found to be selected 2 .wheellifting bail I3I and bail arm n is rocked clockwise through a smallangular distance in opposition to its biasing spring 204, to bring itinto position to initiate or perform its function.

Since tension spring I66 is effective substantially instantaneouslyafterthe printing of a character to withdraw print hammer I69 to itsretracted position, which operation can be performed much more rapidlybyspring I66 than it could be by cam I operating through ball operatinglever I53, the transfer of the next signal combination can be performedsooner after the print operation than it could be with positive printingand retraction of the print hammer; The sooner after the printingoperation that the transfer of the next signal combination may beperformed, the'greater is the interval of time that maybe allotted forrotation of the type wheel into a new stop position corresponding to thenew selection and, therefore, the slower can be the speed of rotation ofthe type wheel shaft 86. The maintenance of minimum rotationalvelocities consistent with emcient operation is desirable in order tominimize inertia effects.

Internal cam I86 is required to hold type wheel I elevated only untilthe print operation has been performed. As cam I 5| continues to rotateand restores print bail operating lever I53 to its extreme clockwiseposition, cam I86 permits bail l3I and bail arm I34 to return to extremeclockwise position, the restoration not being abrupt nor violent butrather being controlled and gradual.

As set forth in the .description of apparatus, cam 202 operates functionbail lever arm I99 to reciprocate the spacing pawl 206 and the functionbars I93. Immediately after the printing of a character has beenaccomplished, the carriage 236 may be spaced to bring a blank portion ofthe page into position to receive the next character. If instead of acharacter having been selected for printing a function has been selected, and the selection evidenced by the clockwise rocking of theparticular function bar by operation of bail I92 substantiallysimultaneouslywith the operation of print bail lever I53, the apparatusis conditioned for the performance of the function. The operation oflever I99 by cam 202 is gradual so that there is no abruptness in theperformance of the function. As the function bars I93 are movedrearwardly of the typing unit by operation of function lever I99,

the one of the function bars I93 which haspreviously been rocked intoeffective position initiates or performs the function such as shift,unshift, line feed, carriage return, and various other desirablefunctions as disclosed in the copending application of Albert H. Reiber,Serial No. 77,796. The operation of function bail lever I99 is the lastoperation performed by the cams on cam sleeve I24 before the cams returnto rest position, at which point, clutch throwout lever I2'I separatesdriven clutch element I29 from driving element I24.

I From theforegoing it will be observed that during the reception ofisolated or widely separated signal combinations, there occurs a trainof operations for each signal combination which begins with the settingin rotation of selector cam cylinder 61 and which ends with thearrestment of main cam assembly I 30.- The selector cam cylindercooperates with the selector mechanism to set up the signal combinationreceived,

trips off the cam sleeve 3' on the front Shaft,

.character spacing andthe performance of any function selected, and cometo rest.

When, however, signal combinations are being received at substantiallymaximum frequency, as

is the case when the transmitter from which the signals are beingreceived is operated by a perforated tape, or ifit is a keyboardtransmitter,

being operated by a skillful operator, the stop time between cycles ofoperation of selector cam signal combination introduced at the selectormagnet 68, whether relating to the printing of a character or to theperformance of a function, will have become effective for the purposefor which it was introduced before the completion of the operationinitiated by the selector cam assembly 61, and there will be no storageof a signal combination requiring an additional cycle of operation ofthe selector cam barrel for its clearing out, as is the case in someprinting telegraph mechanisms, in which thertransfer and printing Ioperations are not assigned to be performed by 6 between the transferoperation and the end of the cycle of the single cam assembly for thecams included in separate cam assemblies, but are performed by camsincluded in a single cam assembly, and in which there is insuflicienttime completion of rotation of the type wheel, or other conditioning ofthe printing element and the actual printing operation. In some printingtelegraph receiving apparatus having a single operating cam assembly,such for example, as that exemplified in the copending applicationSerial No. 77,796, the printing operation is timed to precede thetransfer operation in each cycle ofthe cam assembly so that the printingoperation always lags one cam cycle behind the transfer operation, andat the completion of any message, the signal combination for the lastcharacter or function remains in storage in the code .disc selectormechanism and necessitatesthe introduction of an idle cycle of theselector cam assembly for its clearing out. In the printing telegraphreceiver mechanism according to the present invention, the printingoperation and also the operation of the function mechanism follows thetransfer operation in the general cycle of operation of the mechanismwhich may be considered as beginning with the starting of the selectorcam assembly 67 into rotation and terminating with the arrestment of thecam assembly I30 carried by the main or inner operating shaft. It willthus be apparent that the printer always clears out and prints inaccordance with the last signal combination received The stop time I I2,284,666 and no signal combination is ever left in storage Y in theselector mechanism.

In the foregoing generaldescription of the printing telegraph'apparatusin accordance with the invention, certain details were not describedbecause the description was restricted to Fig. 1

' in which, those details could not be clearly, shown. They are,however, shown in Figs. 2 and 3, and alternative embodiments of theinvention are shown in FigsA to 12, inclusive. The details and thealternative embodiments will now -be described, having referenceparticularly to ,the detailed showings. vii

Type wheel supporting mechanism Type wheel I comprises upper ringelement 26I and lower ring element 262 joined by a web portion which hasradial slots in which type pallets I19 are slidable. As indicated inFig. 2,

the type pallets are recessed, recesses in those of each row openingtoward the recessesof those in the other row, and seated in. therecesses of- Function suppression mechanism In the copending applicationSerial No. 77,796, it, is disclosed that under certain circumstances,

it maybe desirable to suppress functions which would otherwise beselected. For example, it has cured thereto a function suppression plate268, which may be step out on one end and square cut on the other end.When the'function suppression plate 268 is attached in the mannerindicated 'in Fig. 2, with the step cut end at the right, and the longportion thereof at the top, and slide member 201 is in the unshift orrighthand position, the function suppression plate 268 will block'theupper of the projections 26] and will prevent the rocking cf the next tothe lowest function bar I93 into position to be effective.

lifted to its-uppermost position for figures selection, neitherof the'projections261 on the lower function bars I93 will be blocked. Theblocking of" the projections 261 may be reversed by re- 'versing thefunction suppression plate 268 so .function suppression plate 268 willblock neither-- that the edge which is now the upper edge, as it appearsin' Fig. 2, becomes the lower edge, such reversal being effected withoutreversing the plate end" for end. With this arrangement, the

of the projections 261 when slide member 201 is in position for figuresselection, and will block the lowermost of the projections 261,whenslide .member 201 is positioned, for letters selection.

' If the plate 268 is reversed end for end so that sometimes been thecustom to cause the printing of a letter character in responseto aparticular signal combination if the'last preceding caseshift signal wasan unshift or letters signal, and to cause a function to be performed inresponse to the same signal if the last preceding case shift signal wasa shift or figures signal. It is a simple matter to prevent the printingof a character in response to such signal combination when preceded bya, shift or figures combination, it being necessary merely to provide ablank type pallet in the lower row of type pallets at the point wherepallet actuation will occur when the print hammer is operated, but it isnecessary to suppress the function when printing of a character is tooccur from the upper row of type pallets in response to the signalcombination combination. In the apparatus accordingto the disclosure ofthe copending application Serial No.'77,796, the shifting of the typewheel to its letters and figures positions was accomplished by a typewheel supporting frame which was mov able upwardly under the control ofthe shift or figures function bar-,and which remained in that positionuntil restored 'to' its lowermost or letters position by-the unshiftfunction bar. i

ACCOXdlng to the present disclosure, 'shift and it may be desired tosuppress may be provided with laterally extending projections 261.Depending arm 265 of slide member 201 ha sethe square cut end is at theright as viewed in Fig. 2, both of the projections 261 will be blockedwhen slide member 201 is positioned for letters selection, and neitherwill be blocked when the slide member is positioned for figuresselection. I

Operating cam and follower arrangement In the general description whichhad reference particularly to Fig. 1, certain, cam followers and. ,theirfollower arms could not be particularly pointed out and identified dueto the fact that it was necessary to omit them from Fig. 1 in order thatother elements might be more clearly whenpreceded by the lettersorunshift signal shown. Reference is now made to Figs. 2 and 3 foradditional details. Reference numeral 269 designates the roller which isoperated by type controlled is identified, as previously set forth,

l Letters and figures shift mechanism Fig. 3 discloses in detail, bymeans of an ex-.

, 'ploded perspective view, the instrumentalities for shifting theslidable member 201 forward and back under the control of the topmostbar I93 which performs the shift function and of the bar immediatelybelow it which performs the unshift function. In the general descriptionwhich had reference particularly to Fig. 1, the shifting of slidemember201 to its rearmost position was described as being under the control oflever 2I8 pivoted, upon stud I42, which slidably supports slide member201, the screw 2I'9 having been identified as the pivotal interconnection between lever 2I8 and slide member 201.

Referring particularly to Fig. 3, it will be ob' end with an elongatedslot 216, which is adapted to receive the reduced portion 211 of acylindri- When, however, the slide member 201 is shifted to its extremeleft-hand position; in which position it permits type wheel I to be calboss 218, thereduced portion 211 having par-. allel sideszwherebyboss218 isprevented from rotatingin slot 216-. ;-The slot may be longer thanreducedportion-211 of boss 218 to provide for adjustment; of the bosswithrespectto lever 2I8. Screw 2I9 threadedly engages boss 21 rigidlyclamps it to lever 2I8.

In a direct linebe'lowslot 219,

I42,'the slide member is provided with an open ended slot 28], the slotopening downwardly. Slot 28I is dimensioned to receive cylindrical boss218 and to permit rotation of the bus within the slot or movement of theboss longitudinally thereof while affording substantially no lost motionof boss 218 transversely thereof. Boss .218 constitutes an. articulationbetween lever 2I8 andslide member 201 so that when depending finger 22I.of lever H8 is engaged by laterally extending projection 222 of thesecond function bar I93 from the top, and lever 2I8 is rockedcounterclockwise, slide member 201 will be shifted to its rearmostposition.

For the restoration of slide member 201 to its foremost position, thereis provided a lever 282 which is pivotally supported by stud I42 on theopposite side of slide member 201 from lever 2I8, and is provided at itsupper end with an open ended slot 283. Slot 283 is adapted to receivethe cylindrical portion of a boss 284 which is similar to boss 218 andwhich has a reduced portion 286 which enters an elongated slot 281 inslide member 201, .located just below aper ture 2I2. Screw 229threadedly engages boss 284 and adjustably secures the reduced portionthereof in slot 281. Boss-284 constitutes an articulation between lever282 and slide member 201, and when counterclockwise rotation is impartedto lever 282 by laterally extending projection 2220f the topmostfunction bar I93, slide member 201 is shifted, from its rearmost to itsforemost position. Screw 209, which, as previously described, passesthrough slot 208 in slide member 201 and guides it in the slidingmovement which it is intended to receive, is engaged by a spring biasedjockey detent 288 which is pivotally supported by slide member 201 at289 and which is provided in its lower edge with spaced notches 29I.Notches "I in jockey detent 288 engage the shouldered portion of screw209 and prevent accidental movement of slide member 201 out of aselected position to which it has been shifted. Since levers 2I8and 282are both pivoted on stud I42, and pivotally engage slide member .201 atpoints in opposite direction from stud I42, it will be apparent thateach of the levers, upon being rotated by its. associated function barI93, imparts an opposite rotation to the other. The angular position ofeach of the levers with reference to slide member 201 in a predeterminedposition thereof may be varied by loosening the screws 2I9 and 223 andshifting the reduced portion of the bosses 218 and 284 in the slots 216and 281 respectively.

Type wheel oscillating mechanism Fig. 3 shows in completev detail thedual cam arrangement for controlling bail I3I. The cams I25 and I86 areshown in their rest position, cam follower roller 269 engaging cam I25at the by which the" slide member 201 is-slidably supported upon studminimum distance from the axis thereof, and I which is a sharplydescending cam surface, ap-

proaches follower roller 269. Before roller 269 moves down the drop-offI33, the clutch through which rotation is imparted to cam I86. istripped off in a manner previously described, and cam I86 rotates in aclockwise direction through a sufficient angular distance to bring thecam surface portion which is at minimum distance from the axis of camI86, which portion is identified by the reference numeral 292, intoengagement with follower roller 212, whereby bail I3I is held in theposition to which it had been rocked by cam I25. If cam I25 is notimmediately set in rotation by the tripping of its driving clutch, itwill remain in the position shown in Fig. 3 with cam follower roller 269held out of engagement with cam I25 by the internal surface of cam I86.As cam l86 continues to rotate, the point of engagement of followerroller 212 with its internal cam surface recedes from the axis of thecam, thus controlling the return of bail I3I to extreme clockwiseposition. In

In the lower portion of Fig. 3 there is shown in exploded perspective aseries of elements which, when assembled, comprises a roller bearinggrip clutch. Interposed between the main cam sleeve I30 and the shaft bywhich it is supported, there is a sleeve 293 which is fixed to sleeveI30 and is threaded at its lower end. The inner member 294 of a rollerbearing grip clutch is threadedly secured to the lower end of sleeve293. Member 294 fits into the central aperture of ring gear I06 and isretained in close proximity to the hub of gear 18, as shown in Fig. 2.Member 294 has a plurality of substan-- tially right angled notches cutin the periphery thereof, the faces defining these notches being ofunequal length, the shorter of the two faces of each notch designated bythe reference numeral 296 extending substantially radially of the member294. The angularly disposed faces of the notches and the adjacentarcuate inner surface of ring gear I06 define recesses that aregenerally triangular, being bounded by two plane surfaces and a curvedsurface. Each of the short faces 296 of the notches in member 294 isrecessed to receive and support one end of a compression spring 291. Anaxially drilled roller bearing 298 is disposed in each of the generallytriangular recesses and the compression spring 291 tends to wedge theroller bearing between the long face of the notch and the arcuateinternal surface of ring gear I 06. The lower end.

of cam sleeve I30: is undercut to provide a shoulder 299 against which aretainer ring 30I is placed before member 294 is secured to sleeve 293.Retainer ring 30I fits looselyon the undercut portion of sleeve I30 andis not clamped in place,

tion to the inner clutch member.

but is free to rotate. The purpose of ring 30I is to cover, at leastpartially; the rollers 298 and to prevent them from escaping from theirrespective recesses. Depending fingers 302 of ring "I enter the axialbores of rollers 298, the bores being of sufficient diameter to permitconsiderable free movement of rollers 298 laterally of fingers 382.

An understanding of the exact nature of the clutch (Fig. 1) by which camsleeve I30 is driven is prerequisite to an understanding of the utilityof roller bearing grip clutch consisting of member 294, rollers 298, andring gear I06, the roller bearing clutch being used in the presentinvention as a brake. Cam sleeve I30 is driven by driving clutch elementI24 and driven element I29 as previously described. This clutchmechanism is of the well-known one-way driving construction. Each toothof both elements of the clutch has one surface substantially in a planepassing through the axis of the clutch, and the other surface obliquethereto. Should any torque be applied to thedriven element I29 of theclutch which exceeds the torque applied to the driving element I24, thesloping surfaces of the teeth of one clutch element tend to slide uponthe sloping surfaces of the teeth of the other clutchelement, thusshifting driven element I29 axially away from driving element I24 andcompressing sprlng I26. If'the differential between the two torques isappreciable, the driven element may be rotated ahead of the drivingelement a distance equal to the extent of several teeth of the clutchmembers; A torque of sufficient magnitude to cause driven clutch elementI29 to rotate more rapidly than driving element I24, and thus to, gainupon it, may be generated by a heavily biased cam follower such as thefunction cam follower I99 and roller 20I or the print cam follower I53and roller I52 riding down a sharply descending slope of theirrespective cams and thus becoming a negative load upon the driven clutchelement I 29.

The roller bearing grip clutch hereinbefore described serves as a braketo prevent acceleration of cam sleeve I30 under the influence ofnegative load upon any of its cams. Whenever cam sleeve I30 isstationary and th gears 18 and I06 are rotating, inner roller bearingclutch member 294, which is secured to cam sleeve 293 and, therefore,indirectly to cam sleeve I30, is. also stationary, and the frictionalengagement between the inner surface of ring gear I06 and rollers 296tends to move the rollers into the widest portion of the recesses inwhich they are seated, the rollersthus being moved substantially free ofinner clutch member 294 so that there is no tendency of gear I06 toimpart rota- Whcn cam sleeve I30 is released for rotation and isrotating at the same speed as gear I06, there is no relative movementbetween roller bearing clutch member 294 and ring gear I06, and thesprings 291 tend to wedge rollers 298 between the long faces of thenotches in inner clutch member 294 and the inner surface of gear I06. Ifcam sleeve I'30 should be subjected to a torque which tends to rotate itfaster than gears 18 and I06, the frictional engagement of rollers 298with member 294 tends to increase the wedging of the rollers 1298between member 294 and gear I06 so that a positive lock between innerroller bearing clutch member 294 and gear I06 is established and camsleeve I30 is prevented from torque and is held to the speed of rotationof gear 18.

Modified forms of type wheel oscillating mechanism and printingmechanism wheel I44 shown in Figs. 1 and 2, and is. supported forsliding movement on its driving shaft by frame 301. Frame 301 issupported for movement in a vertical direction by stud 308 which.

extends through an elongated slot 309, in frame 301, and the frame isurged .downwardly by spring 3. Gears M2 and 3I3 carried by shaft 8correspond to gears 18 and I06 carried by the maifi shaft in thepreviously described disclosure of Fig. 1, and gear 3I6 carried by shaft3" corresponds to gear I04 carried by shaft I03. Gear 3l8 has securedthereto the driving element 3I8 of a positive drive clutch mechanism,the driven element of which, indicated 3I'9, is connected to cam sleeve32I and is urged to engage driving element 3I8 by compression sp 322.Sleeve 32I supports and drives cam 323, which is arranged to control theoscillation of type-wheel supporting frame 301, and cam 324, which isarranged to effect printing from type wheel 306. l

A lever 326, pivoted on stud 321, supports at one end a cam followerroller 328 which engages the periphery of cam 323 and, at the other end,supports one end of a tension spring 329, the

other end of which engages a laterally extending projection 33l of alever arm 332 also pivoted on stud 321. The free end of lever arm 332 isdisposed below a pin 333, which extends outwardly from type wheellifting frame 301.

When cam 323 is in its rest position, its portion of minimum radius isin alignment with follower mile? 328 so that lever 326 occupies itsextreme clockwise position and frame 301 is biased to its lowermostposition by tension spring 3I I, this position being determined by thearrestment of pin 333 by the free end of lever arm 332, or by arrestmentof frame 301 by the upper end of slot' 309. When the clutch whichcomprises driving element 3I8 and driven element 3l9 is tripped off,rotation is imparted to cam 323 and lever 326 is rotatedcounterclockwise. Lever 326 imparts counterclockwise rotation toleverarm 332 to effectthe lifting of type wheel supporting frame 301,the tension of spring 329 exceedin that of spring 3 so that spring 3Hshall not successfully oppose'the lifting of frame 301 by lever arm 332,which is connected to lever 326 solely by spring 329. Type wheel liftingframe 301 may have associated with it mechanism for arresting it ateither at two levels, according to whether typing is to be effected fromthe upper or lower row of type elements carried by type wheel 306, andthis arrestmentcontrolling mechamsm may be of the kind disclosed inFigs. to 3, inclusive, or alternative structures to be hereinafterdescribed. When frame 301 has been arrested, lever arm 332 will be ableto travel no farther in counterclockwise direction, but lever 326 maycontinue in that direction to the full extent imparted by cam 323, thespring 329 yielding and permitting this excess motion of lever 326.

accelerating in response to the locally applied 74 It will thus beobserved that the apparatus di$- Elsi closed in Fig 4 for elevating thetype wheel is similar in principle to that disclosed in Figs. 1' to 3;inclusive, in that the type wheel elevation is accomplished by acampperating through a yieldable element, the difference being that inthe apparatus, according to Figs. 1 to 3, inclusive,

the yieldable element is disposed between the lifting lever and the typewheel lifting frame, whereas in the apparatus shown in Fig. 4 theyieldable element is placed between operating and operatedlevers, thetwo levers being pivoted upon the same support.

Printing cam 324 is engaged by a follower roller 336, carried by one endof a lever 331, which is pivoted intermediate its end on stud 338. Aprint hammer 339, which may be similar to the print hammer !69 in Figs.1 and 2, is articulated to lever 331 at the end opposite to that whichcarries follower roller 336. A spring 34! biases lever 331 incounterclockwise direction, whereby follower roller 336 seeks continuousengagement with the periphery of cam 324 and the free end of printhammer 339 is normally held out of the path of the shanks of the typepallets. The apparatus for actuating the type pallets shown in Fig. 4does not depend upon overtravel of the print hammer 339 as is the casein the previously described printing apparatus shown in Figs. 1 and 2.Substantially all of the motion of print hammer 339 is positivelyimparted by cam 324 and the retraction of print hammer 338 isaccomplished by spring 34!. It will be understood that'the timing of theoperations performed by cams 323 and 324 is such that cam 323 rockslever 326 to extreme counterclockwise position'to bring type wheel 366into the printing position before the printing blow is delivered by cam324. After the selected type pallet has been operated and during theremainder of a cycle of rotation of cam sleeve 32!, cam 323 may controlthe return of lever 326 to extreme clockwise position and therefore therestoration of type wheel supporting frame to its lowermost position.

Fig. 5 discloses still another combination of arrangements for elevatingand lowering the type wheel and for actuating the type pallets, in whichthe mechanism for elevating the type wheel is similar in principle ofoperation to that shown in Fig. 4. although the arrangement for loweringthe type wheel is considerably different, and in which the type palletactuating mechanism operates by overtravel, and to that extent issimilar to the embodiment of the invention shown in Figs. 1 and 2.Referring now to Fig. 5, it will be observed that a shaft 346, which maycorrespond to shaft 3!1 in Fig. 4, supports cam sleeve 341, which may beclutch driven as in Fig. 4 and which has secured thereto type wheelelevating cam 348 and printing cam 348. SA bell crank 35!, pivoted onstud 352, comprises arms 353 and 354. At the free end of arm 353,'thereis a cam follower roller 356 which is arranged to engage the peripheryof type wheel elevatingcam 348. A

bell crank lever 351 also pivoted on stud 352 comprises arms 358 and36!. The free end of arm 359 of bell crank 351 is articulated to thelower end of type wheel supporting frame 362. Frame 362 is urgeddownwardly by spring 358. A tension spring 363 is distended between thefree ends of arms 354 and 36! of bell cranks 35! and 351, respectively,and spring 363 functions in the same manner as tension spring 328 inFig. 4; namely, to impart motion from lever 35! to lever 351 whileaffording a yield therebetween. Frame 362 supports the hub 364 of typewheel 366 in the same aaeeccc Arm353 of bell crank has integraltherewith a projection 361 which has a laterally ex= tending arm 366. Alatch 369 pivoted at 31! biased in clockwise direction by spring 312 andhas a shoulder 313 which may engage laterally extending arm 368 of bellcrank 35! when the bell crank has been rocked into extremecounterclockwise position by cam 348, so that the bell crank will beretained in counterclockwise position and frame 362 will be maintainedin elevated position without providing a dwell on cam 348. The trippingof latch 363 to permit spring 358 to restore type wheel supporting frame362 to lowermost position and cam follower roller 356 to return toengagement with the periphery of cam 348 will be described later. Aprint bail 316 is pivoted intermediate its ends at 311 and has near itslower end a projection 31 8 which is adapted to engage themriphery ofprint cam 349 by operation of which printbail 316 may be rockedcounterclockwise. A spring 318 biases bail 316 in clockwise directionand at its upper end bail 316 has articulated thereto a print hammer 38!which may be Sim-- ilar to print hammer I68 shown in Figs. 1 and 2.

' Above the projection 318, bail 316 is provided able stop which opposesspring 318 when bail 316 is in rest position, and holds the free end ofprint hammer 38! out of the path of the type pallets of type. wheel 366.In the rest condition of the printing apparatus shown in Fig. 5, thereis agap between projection 318 of print bail 316 and the periphery ofprint cam 348. This gap permits bail 316 and print hammer 38! toovertravel sufficiently to actuate a type pallet. Cam 348 is rotatablein clockwise direction, and as it rotates it imparts counterclockwisemovement to bail 316 thus retracting print hammer 38! from the normalposition and distending spring 318. The drop-off of cam 348 from maximumto minimum radius is extremely sharp and whenprojection 318 of bail 316encounters this drop-off, bail 316 is released and spring 318 rocks bail316 sharply in clockwise direction. Due to the inertia of bail 316 andprint hammer 38! they overtravel to operate a selected type pallet andeffect printing therefrom. In overtraveling, bail 316 depresses plunger383 which in turn compresses its spring slightly. As soon as the kineticenergy of bail 316 and print hammer 38! has been expended, plunger 383restores bail 316 to normal position by rocking it slightly incounterclockwise direction.

Print bail 316 is provided with a depending finger 384 in the path ofovertravel of which is disposed the upper end of latch 369 when thelatch is holding lever 353 in extreme counterclockwise position. It willbe apparent from this i that at substantially the instant that printingis effected, latch 368 is tripped and spring 358 enabled to restore typewheel lifting frame 362 to its lowermost position immediately, andwithout supervisory control by cam 348.

Alternative embodiments of shift and unshijt function mechanism of typepallets selectively. Referring first to Fig. 5, the reference numeral386 designates shift and unshift function bars which may be similar tothe function bars I93 shown in Figs. 1 and 2, and may be similarlyprovided with laterally extending function performing lugs 381. Functionlevers 388. and 389 are pivotally mounted so as to be capable ofoperation independently and individually by the function bars 386. Lever388 is pivotally mounted intermediate its ends, and its upper endpivotally supports one end of a link 39l. The other end of link 39| ispivoted to lever 389 intermediate its ends, and the lever 389 ispivotally supported at its upper end by screw 392. Function levers 388and 389- are provided with arrestment shoulders 393 and 394,respectively. Frame 362 has extending from the opposite sides thereofears 396 and 391 which are so positioned on frame 362, that when theupward travel of frame 362 is arrested by en.- gagement of ear 396 withshoulder 393, the type wheel 366 will be arrested in the lower of itstwo printing positions whereby printing is accomplished by operation ofan upper type pallet, and

when the frame 362 is arrested by engagement of from a type pallet inthe lower row. The pivoting of levers 388 and 389 is such that wheneither is rocked in counterclockwise direction by its assigned bar 386the other is rocked in clockwise direction and is thus brought intoposition,

to be the next to effect a change in case selection. Levers 388 and 389are shown in Fig. 5 in position to permit the type wheel to be elevatedto its uppermost position, shoulder 393 of lever- 388 being-withdrawnfrom the path of car 396. Should the uppermost of the function levers386 be selected and operated, the position" of lever 388 will not bechanged as it already occupies its extreme counterclockwise position.Upon the conditioning and operation of the next function bar 386, thelower end of lever'389 will be engaged by projection 381 and lever389will be rocked counterclockwise. Link 39l will thus be shiftedrightwardly and lever 388 will be rocked -in clockwise direction wherebyits arrestment shoulder 393 will be brought into position to nism isshown. A lever 48] pivoted at 482 has upper and lower arrestmentsurfaces 483 and 484, respectively. A spring biased jockey detent 486has two notches which cooperate with the pointed upper end of lever 48!to determine two operative positions of lever 48I. Below the lower endof lever 48l, arm 359 of bell crank 351 is provided with a lug 481which, moving upwardly as type wheel supporting frame 362 is lifted bycam ,348, comes into engagement with upper arrestment surface 483 whenlever 48l occupies extreme clockwise position, andis arrested by thelower arrestment surface 484 when lever 48l occupies extremecounterclockwise position. Thus. lever 48l determines'the extent towhich the type wheel may be lifted, printing being effected from thelowermost row of type. pallets ear 391 with shoulder 394, the type wheelis 1 arrested in its uppermost position for printing when lever 41 is inextreme clockwise position, and from the upper row of type pallets whenlever 48l is in extreme counterclockwise position. Lever-arms 481 and488, pivoted at 489, are provided for rocking lever 48! from one to theother of its two selective positions. Lever 481 terminates in positionto be actuated by the uppermost of the case shift function bars 386 andlever 488 terminates in position to be actuated by the lowermost of thefunction bars 386. Lever 481 is provided with a laterally extending arm4 which engages one edge of lever 48! between the pivot 482 and theupper end of lever 48l and lever arm 488 is provided with a laterallyextending arm 4l2 which engages the same edge of lever 48| betweenpivot. 482 and the lower end of the lever. Light springs H3 and 4 biaslevers 481 and 488 respectively in counterclockwise direction so as tomaintain their laterally extending arms 4| I and 2, respectively, inengagement with the edge of lever 48l. A fixed stop 6 limits therotation of levers 481 and 488m clockwise direction.

With the apparatus as shown in Fig. 6, should the uppermost of functionbars 386 be conditioned and operated, its operation would be idle,-since the lever 481 already occupies its extreme counterclockwiseposition, and in being shifted into this position has rocked lever 48lto extreme clockwise position whereby the upper arrestment surface 483is in the path of projection 481 carried by the type wheel oscillatingbell crank 351. Lever 488 is at this time held in extreme clockwiseposition by lever 48!. Upon the conditioning and operation of thelowermost of the case shift function bars 386, lever 488 will be rockedto extreme counterclockwise position, and it will impartcounterclockwise rotation to lever 48l. When lever 48I comes to rest inextreme counterclockwise position, its lower arrestment surface 484 willbe in the path of projection 481 so that frame 362 can be lifted onlysufliciently to bring type wheel 336 into position for printifig fromthe upper row of type pallets. As lever 48l is rocked to extremecounterclockwise position, it restores lever 481 to extreme clockwiseposition so that each of the levers 481 and 488, upon being operated,conditions the other to be the next to be operated.

Fig, 7 shows a system of levers between type wheel oscillating cam- 348and type wheel sup porting frame 362 different from those heretoforedescribed, and a somewhat different system of case shift control overthis modified lever system. Referring to Fig. 7, it will be observedthat the operating earns, the print bail, and thetype wheel supportingframe are the same as those shown in Figs, 5 and 6. Instead of springinterconnected bell cranks between cam 348 and frame 362, there is afirst class lever and a third class lever pivoted at H1. The first classlever is designated 8 and it carries a cam follower roller which isengageable with the periphery of cam 348. It also has a latching lug421, similar to that disclosed in Fig. 5, which cooperates with latch389. The third class lever, designated 422, is articulated to type wheelsupporting frame 362 and intermediate its ends itpivotally supportslatch 423 which is spring biased in counterclockwise direction. At theright-hand end of lever 8, as viewed in Fig. '7, there is an undercutportion which provides a shoulder which may be engaged by latch 423, asshown in Fig. 7. When latch 423 is engaging the end of lever H8, and thelever is rocked in counterclockwise direction by. cam 348, the thirdclass lever 42?- is rocked. in counterclockwise direction through thesame angular distance as lever M8 to effect the elevation of the typewheel to, its uppermost position. When, however, latch 423 is rockedin'clockwise directionto disengage it from the end of lever 4H3, thelever may rock in counterclockwise direction without imparting rotationto lever 422 until lever 8 comes into engagement 'with an abutment pin4,24,- carried by lever 422.. After coming into engagement with pin 424,lever 4l 9 will impart rotation in counterclockwise direction to thirdclass lever 422, but-the distance through which lever 422 will be rockedbe less than the distance through which lever 4l8 was rocked, thedifference resulting from the 10st motion which lever 4l8 undergoesinorder to come into engagement with pin 424 and, therefore, the typewheel will be elevateda lesser distance than it is when latch 423 isengaging lever B, the type wheel thus being elevated to position forprinting from the upper row of type pallets.

The case shift control mechanism for the lever system, shown in Fig. 7,may be very similar to that shown in Fig. 6. Levers 426 and 421 pivotedat 428 may be identical with levers 401 and 408. A lever 429, pivoted at43!, may be rocked into extreme clockwise position by lever 426 and intoextreme counterclockwise position by lever 421, and may be held ineither of these selected aasaeee shown in Fig- 1, and may be arranged tobe tripped by the selector cam assembly in thesame manner that clutchthrowout-lever H2 is tripped. Driven clutch element 438 is keyed to acam assembly sleeve 442 which may correspond to cam sleeve N3 of Fig. 1,and may have secured thereto cams for performingany desired functionaloperations; for example, thejtransfer, am I19 and type wheel elevatingcam l251 of I gs land 2. For the sake of simplicity, suchica s have beenexcluded from the showing of Figs, 8.,and 9. Cam assembly sleeve 442 hassecured thereto a cam 443 which corresponds to cam I I8, shown in Figs.1 and 2, and the function of which .;is to set in operation a second camassembly which will now be described.

Below the cam assembly sleeve 442, but, having no direct connectiontherewith, a ratchet 444 is secured to shaft 436. Below the ratchet 444however, lever 429 is rocked to extreme counterv clockwise position, itengages latch 423 and rocks it out of engagement with lever 416 so thatwhen lever M3 is actuated, its rotation will be idle until it comes intoengagement with pin 424 and frame 362 will be elevated only to bring thetype wheel into its lowermost printing position, The operation of lever429, by and upon the levers -42 6 and 421, is the-same as in Fig. 6,lever 429, -upon being actuated by one of the levers 426 or 421,restoring the other to unoperated position.

Alternative embodiments of cam assemblies Reference numeral 436designates a continu-' ously driven shaft which may correspond to theinner shaft in Figs. 1 and 2, which is the shaft that supports anddrives the selector cam assembly 61. Shaft 436 has secured thereto thedriving element 431 of a positive drive clutch, the driven element ofwhich, designated 439, is slidable axially of shaft 436. Driven element438 is urged by compression spring 439 into engagement with drivingelement 431 and is normally held disengaged from driving element 431 by4 corresponds to'clutch throwout lever H2,

' clutch throwout lever 44 l Clutch throwout lever a disc 446 isjournalled on shaft 436 so as to be capable of remaining stationarywhile shaft 436 is rotating. Disc 446 carries a pivoted pawl" 441 whichis urged by a spring 448 into engagement with ratchet 444. Adjacent tothe point at which pawl 441 pivotally mounted, disc 446 is provided withan indentation 449 in the periphery thereof which is of suflicient depththat when pawl 441 engages ratchet 444, the tail of pawl 441 swings outover a portion of the inden tation. A pawl controlling lever arm 45! ispivotally supported at 452 and is biased in clockwise direction asviewed in Figs. 8, 9, and 1.0 by spring 453. Below the disc 446, a cam454 is joumalled on the shaft 436 so that the cam may be withheld fromrotation while ,shaft 436 is rotating. Disc 446 isprovided with anarcuate slot 456, and a clamping screw 451 passes through slot 455 andthreadedly engages cam 454 for securing the card to disc 446. Springbiased bail 458, which may beany element that is to be operated by cam454, such as, for example, a printing bail, supports at its free end afollower roller 459 which engages the periphery of cam 454.

The retention of cam 454 in rest, or idle position is accomplished bythe free edge of pawl controlling lever arm 45! which engages theinnermost portion of indentation .449 in disc 446, thus serving as adetent for disc 446 and cam 454,

and engaging the tail of pawl 441 to hold it out of engagement withratchet 444. Clamping screw 45'! and slot 456 afford a wide range ofadjustment of cam 454 with respect to disc 446 so that the rest positionof cam 454 may be varied and the desired relation between cam 454 andits follower roller 459 established. Cam 443, carried by cam assemblysleeve 442, has a portion of sufficient radius, as indicated in dottedlines in Fig. 10, to rock lever arm 45l counterclockwise, whereupon therestraint upon pawl 441 is released and spring 448 rocks it intoengagement with ratchet 444. Cam 443 may be positionel on sleeve 442 soas to rock lever arm 45I free of pawl 441 at any time during a cycle ofrevolution of sleeve 442, the only limitation being that in its positionof arrestment it shall not permit pawl 441to engage ratchet 444, wherebycam 454 would be rotated continuously. As soon as pawl 441 is broughtinto engagement with a toothof ratchet 444, which rotates continuouslywith shaft 436, rotation is imparted to disc 446 and, therefore, to cam454. Pawl 44'| thus moves out of range of pawl controlling lever arms45l, which in'turn is maintained in extreme counterclockwise position'byriding against the periphery of disc 446. During the rotation of cam454,cam sleeve 442, con-

